Feed control foe hammer mills



Sept. 2, 1952 T, M, MOORE 2,609,153

FEED CONTROL FOR HAMMER MILLS Filed Oct. 13, 1948 Satente Sept. 2l,

FEED CONTROL FOR HAMRIER MILLS Thomas Munsey Moore, deceased, late of Salem, Va., by The Bank of Salem, administrator, Salem, Va., assignor to Moore Milling Company, AInc., Salem, Va.; a corporation of` Virginia Application October 13, 1948, Serial No. 54,272

. Claims. Y 1 Y ,This invention relates to a feed control for hammer mills.

'The primary object 'of the invention is to control the feed of material to the mill so that it is` substantially `held in a state of suspension during hammer impact irrespective of the nature of the material being ground.

Another object of the invention is to provide afeed control adapted to be installed in a previously built mill or built withthe mill that results in suspension grinding of the material without a material change of conventional mill structure.

A further object of the invention is to permit anadjustment of the control for use with different materials without' a change of the pre-set arrangement of parts necessary for suspension grinding during the milling operation Still another object of the invention is to provide means for adjusting the control from the exterior of the mill so that any desired changeover may be made during continuous operation of the hammers.

Still another object of the invention is to eliminate the possibility of choking the mill in operation due to the retarded material flow necessary for suspension grinding.

These and other objects of the present invene tion will appear as the following description thereof proceeds, and in order to more clearly understand the invention, references may be had to the accompanying drawings in which an embodiment of the invention is shown.

In 'the drawings: j

Figure lis a fragmentary perspective showing the'feed control applied to a hammer mill.

Figure 2 is a vertical section through the mill head with certain parts in elevation showing the grinding operation.

Figure 3 is a similar view showing in dotted linesdifferent positions of the control. Y

Figure 4 shows the operation nut of the control adjustment. Y

In a Vconventional"hammer mill of the rotary hammer type thematerialto be ground is fed at the top of themillusually at one side into and against the upper 'are of :the throw of the hammers which rotate in .the same direction with respect to the 'jflow. This results in a helter skelter throw of. the material in the mill head upon` hammer'im'pact and subeicient grinding. Unground material is `bounced around in the head before actual hammer. impact causing excssive wear against the back'wall and unless the fedlcontrol'is"continually supervised an underfeed or overfeed results. The ideal grinding con# dition is where the feed is such that the material fed to the rotary hammers is loosely held by its own weight in a state of suspension so that substantially only ground material passes to the usual concave screen in the bottom of the mill. This is the objective of the invention disclosed.

As the mill disclosed is primarily for grinding grains or the like and as the weight of such materials vary, an adjustment to compensate for such variations without destroying the presetting for suspension'grinding is essential. In other words the control is pre-set for the type.` of material to be ground, such as wheat, oats, rye, etc., so as to result in suspension grinding during rotation of the hammers. When a changeover is made to another say free flowing material, the control may be given a compensating adjustment without altering the pre-set arrangement for suspension grinding and also without disturbing the continuous operation of the mill.

For the purpose of illustration there is shown a hammer mill having the usual flat sides I, with rotary hammers 2. Only the upper half of the hammers are shown and it is well understood that the lower part of the mill includes the concave screen and fan, not illustrated. The mill includes the usual top and back cover 3 terminating short of an upper side feed trough 4,.as at 5, to provide an air feed 6. The trough 4 is inclined and has an extension 'I to direct the material into the hammers 2 in the upper arc of their throw in the same direction of their rotation and to one side. This is conventional hammer mill structure and forms no part of my invention. There is provided across the troughV 4 a protector plate 8 adjustably mounted in end brackets 9 secured preferably to opposite sides of the mill. This plate is not a feed control but merely prevents free owing material like wheat, oats `or the like from filling up the entire trough andchoking olf the air inlet or feed 6. When bulk material such as hay or ear corn is being ground it may be swung out of the way.

To obtain suspension grinding there is sus" pended entirely across the top of the mill a rigid unperforate plate IE, usually formed of cold rolled y steel. This plate is positioned substantially'as shown in Figure 2 and being arranged adjacent the feed inlet acts as a baiile to control the inlet flow of material to be ground and restrict the area of hammer contact. The plate II) is so' mounted that its upper edge I I is always spaced below the top 3 of the mill to permit a continuous flow of air thereover as indicated by arrowsV inlet side of the plate I will beV held in suspen= sion and in a state of agitation against the baille plate so that a very effective grindingaetion-oce' curs from the impact of the 'hammers on this freely suspended mass. Practically AYallthe mater rial that passes under the lower edge of the plate is ground so consequently the wear on the back of the mill is greatly reduced. The operation ofv a mill with this type of control in the top is about one-thirdmore emcient than without it.

"'Ijhepre-setti'ng of j thelower edge I2 of the plateflfwith respect to the arc of the throw of the" hammers is important as this space is maintained4 for all free flowing materials. The protector plate 8 in the trough 4 does not control the inlet flow of material and only protects the air inlet;` Also the'spacing of the upper edgey II from' the top of the mill is a necessary feature. While some'air Would of course pass through the material and beneath the lower edge of the plate this is not enough for the proper functioning of the mill."y The positioning ofthe plate Iacross the top of the mill in line with the throw of the materialfrom the hammers necessarily retards the normal air flow so air flow means around the baliie plate must be provided that is not obstructed by the material being ground. In Figure 2i's'illustrated the position the unground materialtakes during mill operation. It rises to near the top 'of the plate Illand its top surfaceis in undulating waves during operation of the rotary h'a'irrn'ers.`

As.' before stated itis necessaryto adjust the baflelp'late I0' formaterials' lof ldifferent weight Without however disturbing the pre-set arrangemeitforsuspension grinding. This is accomplifshed by mounting on'opposite inner facesof sidewallsA ofthe mill that are at right angles tofthef'aiiis of the hammers two tracks I3 which'are preferablyv curved Vtllroughout'their effective lengths substantially parallel' with respeet *to 'arcjof the outer throw of the hammers anbeyndthe same. The ends I4 of the plate Iwhich are close to said side walls have notches I5 adjacent the upper edge II thatengagenover sai'dftracksr` southat the plateiIU is held and guided thereby.

YIfo permitv adjustment of the plate Igalong the arcofthe throw of Vthe hammers V2 and towardand from the mill inlet there is provided along screw' I6 4having its inner endrigidly conncted with the plate I0 by projecting through apening medially adjacent the lower edge I2 and he1d`i'n'po's'ition by opposed inclined faced nuts II. vThe outer end of the screw extends y through a housing I8 in the rear ofthe top 3v A universal joint of the ball and screw-I 6 -lengthvviseV through *the nut 20,@` either in or out of the mill. This operation will move the plate I0 along the tracks I3 toward or from the inlet. Various positions of the plate are shown in dotted lines in Figure 3. For free flowing materials such as wheat, oats, rye, etc., the adjustment would be around the upper arc of the hamflrrlerst Forhlllkv materials. Such ashay 0r earycorn the plateIU is Hback edftothefrear limit onthe tracks I3.

From the foregoing description it is apparent that a hammer mill equipped with the type of feed'jcontrol4 disclosed will suspend the incoming material in a loose mass having a restricted area of hammer Contactk at the upper arc of the throw of the hammers. lThe control or baille plate acts as a regulator distributor, baille and spreader for the fcd'mate'rial and'regulates, restricts and distributes the material so that the amount fed is effectively impacted over the entire width of the'hammers. Practically only ground material passes under the lower edge of the plateso undue wear onthe back of the mill is eliminated. adjustment of the control platetowardor' from the material inlet permits ra c h ahgeov`e' 1 'fory dif-fV ferent materials u without disturbing the I'n'eset1- adjustment for suspension grindingdoj-shitti'rigff down the mill. As this'adjustm'entfis'fromj theQ exterior of the mill it mfyfbefaccomplishedin' a few'seconds without the necessityfffop'ening upA the mill. As the: control vor 'baiileplateiu LiL- ally cuts down thesize ofY the v grinding c'hjambe, theadequate. air' 'feed thrueh, the QPL idf' th' mill and over the plate is al necessary feature..l Without such aA provision they millwould-.cho'ke'f This 'feed vwrltlolfis 'practically 'a unitarystru5 turevthat may Ihe intalled"in previouslyfb lt,- mlns or ybuilt withY themiu.' AftefoeSetnQj further attentionis required on'thepart-olfjt'h'`. Operator andthe `only adjustmentis the chang over forwdiferent materials." The' rrioreeff e'c':t' i'\'{e. A

` 'grindingactionwhas Ybeenfound,to prolong the life.

of the screen" byV 'reducing the arnoi'mtfo'f groundY material passing 'thereoverf-I.' i This applicationis a continuationinepartof application Serial .Nol 49,762'fileselifbpnn `What is claimedis 1 1. A feed y control for hammer mills including rotating hammers,V al material feed ,-inlet, atv the top 'of Vthe mill Yto flow materialfto, befgroun'd' into the upper arcjo'f the thrW., of .the at one side fthereof, af pre-set baffle plate egttending across the mill top f adjacent the inlet, in une with the throw' of'rate'iiaiioyftne ,hammers, said baffle plate being 4 positioned substarr tially radially with,respectftofthe' axis offthe hammers" and Aspaced vabove the ,a1jc v1 of, the hammerthrowand Abelow the top1 of the mil1, curved I'supporting tracks for f saidhbailie v plate secured to opposite sideszof the mill, said. .tracks being substantially parallel tothe arc yof throw of the hammersmeans to move Sadbaiie'p'late alongy said tracks including a screw'hlayinglpne end rigidly connectedwith, said plate a'ndfexi tending throughthewall 'off tl`1'efmill'aniitxfor, vsaidscrew universallyfmointed in the wallof'.,

the mll, and a' Crank for rotating' Said] r'1`ut eXterioif of the mill.. x

'2.. A feed control forhammergmills including rotating hammers, a materialfeed inlet yatftl'ie l' topj'of the H1111 't0 flowi material..tofbeerpundj' intothe upper arc ofjthe throvll'` Oi thev hammers lj in vthe same 'direction 'of rotation andja't one;y Side thereof., a .separateunitaryset heme-Imate having a top and bottom edge clearance with respect to the mill head and throw of the hammers for unobstructed cw of air and material, tracks in the mill head upon which the bale plate is mounted, and means to move the baille plate along said tracks toward or from the incoming Iiow of fed material to maintain suspension grinding for various types of material to be ground.

3. A feed control for hammer mills including rotating hammers, a material feed inlet at the top of the mill to ow material to be ground into the upper arc of the throw of the hammers in the same direction of rotationand at one side thereof, a separate unitary set baffle plate suspended across the top of the mill head and having a top and bottom edge clearance with respect to the mill head and throw of the hammers for unobstructed flow of air and material,

tracks in the mill head upon which the baille plate is mounted, means to move the baiile plate along said tracks toward or from the incoming ilow of fed material to maintain suspension grinding for various types of material to be ground, and said means being operable from the exterior of the mill.

4. A feed control for hammer mills including rotating hammersfa material feed inlet at the top of the mill to flow material to be ground into the upper arc of the throw of the hammers in the same direction of rotation and at one side thereof, a separate unitary set baile plate suspended across the top of the mill head and having a top and bottom edge clearance with respect to the mill head and throw of the hammers for unobstructed ow of air and material, curved supporting tracks for said baiiie plate secured to opposite sides of the mill head, said tracks being substantially parallel to the arc of throw of thehammers, and means to move the baffle plate along said tracks toward or from the incoming flow of fed material to maintain suspension grinding for Various types of material to be ground.

6 5. A feed control for hammer mills including rotating hammers, a material feed inlet at the top of the mill to flow material to be ground into the upper arc of throw of the hammers in the same direction of rotation and at one side thereof, a separate unitary set baffle plate suspended across the top of the mill head and having a top and bottom edge clearance with respect to the mill head and throw of the hammers for unobstructed flow of air and material, cooperating means between the baille plate and mill top permitting movement of the baiiie plate toward or from the incoming ilow of fed inaterial without disturbing the clearances of the set position, and adjusting means to move the set baiie plate in the mill head toward or from the incoming flow of fed material to maintain suspension grinding for various types of material to be ground.

THE BANK OF SALEM. Administrator of the Estate of Thomas Munsey Moore, Deceased,

By A. M. BOWMAN, JR. Trust Ocer.

REFERENCES CITED The following references are of record in the file or this patent:

UNITED STATES PATENTS Number Name Date 781,748 Smith Feb. 7, 1905 1,120,250 Sturtevant Dec. 8, 1914 1,200,104 Haskell Oct. 3, 1916 1,457,210 Crane May 29, 1923 1,553,293 Sturtevant Sept. 8, 1925 2,008,841 Sherman July 23, 1935 2,145,728 Mankoff Jan. 31, 1939 2,224,442 Mankoff Dec. 10, 1940 2,241,667 Mankoff Mar. 13, 1941 2,287,799 Hartshorn June 30'. 1942 

